Production amount of polyurethane foam, which is fabricated by using raw materials imported at expensive cost, is assumed as a volume of about 450 to 500 thousand tons per year when taking the usage of the imported raw materials in to consideration. The polyurethane foam is used for various purposes in various fields. For instance, the polyurethane foam is used as insulating materials for household electronic appliances including refrigerators or construction panels. However, the treatment of the used polyurethane foam is not easy and reclamation or incineration is mainly used for treating the used polyurethane foam.
In general, since the polyurethane foam is a thermosetting resin, the polyurethane foam is not melted by heat and the recycling of polyurethane foam is not easily achievable. In addition, even after the polyurethane foam is incinerated, nitrogen and aromatic ring contained in the polyurethane molecules may remain. Also, in the case of the polyurethane foam used as the insulating material, Freon (CFC) serving as a foaming agent remains in the polyurethane foam after incineration. The nitrogen contained in the urethane generates nitrogen dioxide, thereby causing environmental contamination. In addition, the nitrogen generates fluorine, causing difficulty in treating the polyurethane through incineration. Further, since the polyurethane foam represents a low density, reclamation of the polyurethane foam is not easy, and since the polyurethane foam is hard-resoluble material, reclamation of the polyurethane foam is rarely allowable.
Accordingly, there is a need for developing a technology capable of effectively recycling the waste polyurethane foam.
In this regard, applicant of the present invention has filed a method for manufacturing urethane foam concrete by mixing cement, sand and water with squeezed urethane foam as represented in Korean Patent Registration No. 391558. However, the use of sand is necessary in the technique described above, so the amount of sand used for construction has been increased, thereby causing a shortage of natural sand. Accordingly, the urethane foam concrete representing the above effect without using sand is needed.